It is common and important to classify and count leucocytes to diagnose various diseases using the whole blood of patients in the field of a clinical test.
Up to now, many patents in regard to devices and methods for classifying leucocytes have been reported. For example, a method for dividing leukocytes into five types using two reagents has been disclosed in China Patent Application No. 95115317.X. Said two reagents both contain nonionic surfactant and buffer, and the first reagent further contains at least one ionic surfactant and one organic compound having an anionic group, to divide leukocytes into four groups, lymphocytes, monocytes, eosinophils and basophils plus neutrophils, and the second reagent further contains at least one ionic surfactant, to divide blood cells into basophils and other cells. Thus, Leukocytes are classified into five types by the combination of the two results. The measurement method used is laser scattering measurement.
Besides, U.S. Pat. Nos. 5,677,183, 5,618,733 and 5,731,206, and a Chinese Patent Application No. 88101677 also disclosed the method for dividing leucocytes into five types based on the signals of the scattered light from two channels.
It is found, however, that monocytes are usually classified as between the lymphocytes and neutrophils when classifying leucocytes using the conventional methods mentioned above. The clustering effect is not obvious, which results in an inaccuracy of classification.